300kVA Three-Phase Pad-Mounted Transformer — 13.8kV D - 480Y/277V

Dead-front, liquid-filled, 13.8kV class to 480Y/277V — 361A at the secondary. Sourced to spec from our manufacturer network, with firm pricing inside one business day.

Sourcing

Sourced to your spec — not from a shelf

We procure each unit to your exact specification from our manufacturer and supply-partner network — fluid, feed configuration, taps, and accessories confirmed at quote. Tell us your requirement and need-by date.

Sourcing

Procured to your exact spec from our manufacturer and supply-partner network

Lead time

Quoted per unit and configuration — confirm with your need-by date

Quantities

Single unit or project quantities

Quote turnaround

Firm quote within one business day

Adjacent ratings and primary voltages are sourced routinely — compare the other ratings in this range below, or see the full 300–3,000kVA range on the MV Pad-Mounted Transformers page.

Specification

300kVA — key ratings

Nameplate ratings below. Secondary and primary full-load current are calculated from the kVA and voltage; taps, impedance, dimensions, and weight are confirmed against your spec at quote.

Type

Dead-front, liquid-filled, pad-mounted, three-phase

Rating

300kVA

Primary

13.8kV

Secondary

480Y/277V, 3-phase 4-wire

Secondary amps

361A at full load (FLA)

Primary amps

12.6A at full load (FLA)

BIL

95kV (15kV class)

Fluid

Mineral oil — FR3 (less-flammable) available at quote

Feed

Loop-feed or radial-feed — specify at quote

Taps

±2 × 2.5% (four 2.5% taps) — standard; other arrangements on request

Impedance

Fixed by the factory for this rating; value confirmed on the nameplate and in the quote package

Standards

IEEE C57.12.34 / C57.12.28 · UL/cUL listed

Warranty

5 years from date of shipment

Documentation & delivery

What you get, in writing

Quote package

Firm unit price, lead time, and delivery terms in writing — within one business day.

Nameplate data

Full nameplate on request — taps, impedance, and BIL confirmed against your spec.

Outline drawing

Dimensioned outline drawing for pad planning and site layout, on request.

Test reports

Factory routine-test reports available on request.

UL listing

UL/cUL listed — file number provided on request.

Delivery

Crated for flatbed shipment. Freight quoted to your site; delivery terms confirmed at quote.

Selection & planning

300kVA — what it serves and what it draws

300kVA is the small end of the dead-front pad-mount range. It is specified for distributed service points — small commercial sites, cellular and pump-station loads, temporary services — where a single large unit would oversize the loop. The secondary delivers 361A at 480Y/277V.

A 300kVA unit supplies 240kW of real power to a load at 0.8 power factor, or 270kW at 0.9 — the kVA rating is fixed, the kW delivered depends on the load's power factor. Worked example: a 200kW load at 0.8 power factor draws 250kVA — 83% of this unit’s rating — which is normally the point at which a designer either accepts the margin or steps to the next standard rating.

Secondary full-load current

361A at 480Y/277V (300 × 1,000 ÷ (1.732 × 480))

Primary full-load current

12.6A at 13.8kV (300 × 1,000 ÷ (1.732 × 13,800))

Continuous duty

Rated for 100% continuous load at nameplate (361A). A transformer is not derated for continuous duty — size the secondary overcurrent protection and conductors per NEC 450.3 and 240.21(C).

Real power at load PF

240kW at 0.8 PF · 270kW at 0.9 PF

Physical data

Weight, oil volume, and enclosure footprint are fixed by the factory for your configuration and are issued as a dimensioned outline drawing with your quote. Nominal planning figures across the range are on the MV Pad-Mounted page.

Compare

Other ratings in this range

Secondary full-load current for each rating, so you can size up or down against your calculated load.

Rating	Primary → Secondary	Secondary amps
300kVA	13.8kV D - 480Y/277V	361A	This unit
750kVA	13.2kV D - 480Y/277V	902A	View →
1,000kVA	13.8kV D - 208Y/120V	2,776A	View →
1,500kVA	34.5kV D - 480Y/277V	1,804A	View →
2,000kVA	34.5kV D - 480Y/277V	2,406A	View →
2,550kVA	34.5kV D - 480Y/277V	3,067A	View →
3,000kVA	34.5kV D - 480Y/277V	3,609A	View →

Adjacent ratings and voltage classes are sourced routinely — the full 300–3,000kVA range is on the MV Pad-Mounted Transformers page. MV dry-type (core & coil) units have their own page: MV Dry-Type.

FAQ

Common questions

How many amps is a 300kVA transformer?

At 480Y/277V, a 300kVA transformer delivers 361A at full load (300 × 1,000 ÷ (1.732 × 480)). The primary draws 12.6A at 13.8kV. The transformer itself is rated for continuous duty at nameplate — 361A. The 125% rule applies to branch-circuit and feeder conductors, not to the transformer; size the secondary conductors and overcurrent protection per NEC 450.3 and 240.21(C).

How much does a 300kVA pad-mounted transformer cost?

Pricing is quote-based — it moves with the market and your exact configuration. Request a firm quote and you will have it within one business day; a budgetary price schedule is available on request.

What is the lead time?

Lead times depend on the specification and manufacturer scheduling — quoted per unit. Tell us your need-by date and we confirm the ship window at quote.

Do you keep this unit in stock?

We don’t hold a fixed stock list — each unit is procured to your exact specification from our manufacturer and supply-partner network. Share your requirement and need-by date, and we confirm availability and lead time at quote.

What documentation comes with the unit?

Full nameplate data, a dimensioned outline drawing, factory routine-test reports, and the UL file number — all available on request.

What warranty applies?

Five years from date of shipment, covering windings, core, tank, and terminals. Full terms in our Terms & Conditions of Sale.

Can this unit be supplied in a different voltage or configuration?

Yes. Primary and secondary voltage, taps, fluid, feed arrangement, and accessory package are all confirmed at quote. Adjacent ratings and voltage classes are sourced routinely.

Request pricing for this unit

[email protected] · 718-973-0281

Pre-filled with this unit — edit the request freely.

Beyond transformers

Transformers are our main focus, but we are able to source other electrical equipment to fulfill project needs. Among these include motors, generators, and various types of switchgear. Sourced through the same supply channels, one PO, and the same point of contact ensures consistency and reliability across the board.